Saw chain connection



Sept. 7, 1965 w. H. AITKEN SAW CHAIN CONNECTION Filed Jan. 4, 1962 fr; Mentor.- MAW/am A/tken 6% H :34 WI m Attorngqs.

United States Patent 3,204,672 SAW CHAIN CONNECTION William H. Aitlren, Park Forest, Ill., assignor to Remington Arms Company, Inc., Bridgeport, Conn., 11 corporation of Delaware Filed Jan. 4, 1962, Ser. No. 164,295 2 Claims. '(Cl. 143-135) This invention relates to an improved connecting means by which the terminal ends of a straight section of saw chain are connected together to form an endless chain. More specifically, the invention is directed to a combination connecting-gage link which, when used with a connecting link and a removable connecting pin, performs both as a detachable connection and as a depth gage. The invention is particularly useful when an odd length of saw chain is to be connected to form an endless chain.

It is an object of this invention to provide a saw chain whose ends can be easily and quickly fastened together or unfastened when necessary. This feature of easy detachability is especially important in mounting and unmounting the saw chain on the chain guide bar.

It is another object of this invention to provide a saw chain link element adapted to act as a connecting element and a depth gage.

It is another object of this invention to provide a single link element which performs function now accomplished by two separate elements.

It is still another object of this invention to provide a novel, easily detachable connecting-gage means for a saw chain especially useful when the normal sequence of cutter links is disturbed because of an odd length of saw chain.

Other objects and advantages will appear in the following specification, claims, and accompanying drawings in which:

FIGURE 1 shows an odd length of chain and including a connecting-gage link between excessively spaced cutter links.

FIGURE 2 shows an odd length of chain includinng a connecting-gagelink mounted opposite to two consecutive cutter links on the same side of the chain.

FIGURE 3 shows a prior art odd length of chain showing a separate gage link and a connecting link.

FIGURE 4 shows an exploded view of an odd length chain having a connecting-gage link.

A common type of shaw chain in use today includes a series of central drive links 1 connected by a series of pairs of side links 2 pivotally connected" to the drive links on opposite sides thereof. Every fourth side link on each side is replaced by a cutter link, the cutters on one side being staggered from the cutters on the opposite side and also being of the opposite hand. In other words, the cutters 3R on one side are right-handed and the cutters 3L on the other side are left-handed. This sequence of regularly spaced, staggered, allochiral cutter links is in extensive use today and is desirable for many reasons, some of which will be explained below.

It must be appreciated that there are various other cutter link sequences in use and still other possible sequences which can be used. It is not the intent to limit the present invention to any specific sequence.

It can be seen in FIGURE 4 that each side link 2 and cutter link 3R or 3L has a pair of small diameter apertures 4 and 5 respectively through which the rivet shanks 6 and 7 of rivet 8 protrude. On the other hand, each drive link 1 has a pair of enlarged apertures i in which the enlarged central portions 10 of rivets 8 fit and pivot.

Each cutter link includes a cutter element 11 at the rear of the link and an upwardly and forwardly projecting depth gage portion 12 at the front end of the link. The depth gage portion does not extend outwardly quite as far as the cutter element 11 and functions to limit the depth of the cut and to support the saw chain between the spaced cutter elements.

A problem arises when the desired sequence explained above is interrupted :as, for example, when the ends of an odd length of chain are connected to form an endless chain. For the sequence explained above, an odd length of chain is any chain which has a number of drive links which is not divisible by four. If the number of drive links is divisible by four, the sequence will be maintained when the ends of the chain are connected together. If there are an odd or an even number of drive links not divisible by four, the result will be a greater distance between cutters or two adjacent cutters on the same side.

FIGURE 3 shows a saw chain having an even number of drive links not divisible by four. In such cases there is a non-uniform sequence which results in excessive spacing between adjacent cutter links 3R and 31 on the now-connected opposite ends of the saw chain. In order to break up this spacing, a gage link 13 is inserted in the chain.

The excessive spacing of the cutter links is to be avoided especially when the chain saw is to be used to cut small articles such as small trees, limbs, etc. One of the problems which causes trouble arises when the excessive length of chain in the non-uniform sequence drops down over a tree limb or other piece to be cut of lesser width than the distance between adjacent cutter links. In this situation, the limb hits against the depth gage portion of the next cutter link and causes a thump. The chain may then grind to a stop because the cutter element following the bumped depth gage takes too big a cut out of the wood.

The gage link 13 has an upwardly, forwardly projecting gage portion 14 which bears against the wood and prevents the chain from falling down over a smaller limb or other member being cut. The result is a much smoother cutting action especially when cutting narrow logs. In the past, gage links having small aperture 15 of the same diameter as apertures 4 and 5 in the side and cutter links respectively were provided at the ends of the saw chain and riveted to the terminal drive links.

In order to provide flexibility in installing and removing the saw chain from the guide bar, it is advisable to provide an easily detachable connection whereby the saw chain can be easily connected or disconnected. This necessitated the breaking of the chain at another point and substituting a pair of connecting links 16 for a pair of side links 2. Each connecting link 16 includes a small aperture 17 of the same diameter as apertures 4, 5, and 15 and a larger aperture 18 having the same diameter as aperture 9 of the drive links. The ends of the connecting links 16 having the small apertures are secured to one end of the chain by inserting a rivet therein and setting the rivet. The larger apertures 18 are aligned with the aperture 9 of the end drive link of the opposite end of 3 the chain and a connecting pin 19 of slightly less diameter than the aperture is slidably inserted. Pin 19 can be easily pushed out by hand and the endless chain broken. (See FIGURE 3.)

It can be seen from FIGURE 4 that connecting pin 19 consists of three substantially equal-diameter land portions 19a separated by two grooves 1912. Pin 19 is positioned Within apertures 22, 9, and 18 in such manner that the middle land portion provides a bearing surface for the terminal drive link 1. Moreover, when pin 19 is properly positioned, the ends of connecting link 16 and connecting-gage link 2% are in longitudinal alignment with the two grooves so that when the saw chain is being used, the tension of the saw chain permits the ends of links 16 and '20 to move longitudinally in these grooves and thus the two outer land portions of pin 19 are not in exact alignment with apertures 22 and 18 and thus the pin 19 cannot become disengaged. When the saw chain is not in use, the links 16 and 20 can be moved to line up with the drive link 1 so that when the three apertures are in alignment, the pin 19 can be either pushed out by hand or with some punch means, depending on the degree of tightness between the central land portion and aperture 9.

Thus, prior to the present invention, in instances Where an odd length of chain resulted in a non-uniform sequence of cutter links, it was possible to provide an extra depth gage and an easily detachable connecting means by performing two distinct and time consuming operations. These are: (1) After determining the forward direction of the chain, a gage link is riveted to the terminal drive links so as to be on the opposite side of the drive links from the cutter link in front of the gage link; (2) Breaking the endless chain at another point and providing an easily detachable connecting means by utilizing a pair of connecting links, a connecting pin, etc.

The present invention is designed to perform the same functions as before in a single and much simpler operation. The critical element of the present invention is a connecting-gage link 20 having a small diameter aperture 21 at one end and a larger diameter aperture 22 at the other end. Aperture 21 is the same diameter as apertures 4, 5, and 17 of the side links, cutter links and connecting links respectively. Aperture 22 is the same diameter as apertures 9 and 18 of the drive links and connecting links respectively.

Connecting-gage link 20 also has an upwardly and forwardly projecting depth gage portion 23 mounted on the end of the link having the small diameter aperture 21. This is done to give more link surface area at the point where shock forces transmitted through gage portion 23 are absorbed by the link 20'. Gage portion 23 is designed to give support to the chain between excessively spaced cutter links. It also acts as a stabilizer where an odd length of chain results in two adjacent cutter links being mounted on the same side of the drive links (see FIGURE 2).

Experience has shown that where two cutter links are consecutively mounted on one side, the chain saw tends to drift later-ally toward that side. By providing a gage link or a connecting-gage link on the side of the chain opposite to the consecutively mounted cutters, the saw does tend to stabilize and overcome this lateral drifting.

Connecting-gage link 20 performs as a depth gage and also as an easily detachable connection. The end of the connecting-gage link having the small aperture 21 is securely attached to one end of the saw chain by rivet means while the end with the large aperture 22 is detachably mounted to the other end of the saw chain by inserting connecting pin 19 through aligned apertures 22, 9, and 18 of the connecting-gage link, end drive link, and the connecting link respectively. As explained above, connecting pin 19 is easily pushed out with the hand by using any form of punch means. Inasmuch as the depth gage portion is mounted on the connecting link, the connecting operation is simplified considerably and the extra chain breaking operation is eliminated.

What is claimed is:

1. In a chain saw cutting apparatus wherein the saw chain normally comprises a series of central drive links, a series of pairs of side links, means pivotally connecting said pairs of side links to said drive links including cutter link means mounted at predetermined distances on alternating sides of said drive links, each of said cutter link means including a depth gage portion and a cutter portion, the improvement in an odd length saw chain comprising: readily detachable connecting means connecting the free ends of said odd length saw chain which when connected results in irregularly spaced cutter link means, said detachable connecting means comprising a connecting link and a connecting-gage link positioned in abutting relationship on opposite sides of a first terminal drive link and each having an end portion pivotally mounted thereon, enlarged apertures in the free ends of said connecting link and said connecting-gage link having approximately the same diameter as an aperture in the free end of a second terminal drive link, a connecting pin having portions thereon with the same configuration and slightly less diameter than said enlarged apertures so that upon alignment of said enlarged apertures, said connecting pin can be slidably and removably mounted in said apertures to secure the free ends of the saw chain together, means on the connecting pin cooperating with means on said connecting link and connecting-gage link to permit a relatively minor amount of longitudinal movement of said connecting link and connecting-gage link relative to said second terminal drive link when the saw chain is either in tension or compression thus moving the enlarged diameter apertures out of alignment and preventing the connecting pin from becoming disengaged, and a depth age portion projecting upwardly from said connecting-gage link to take up some of the void formed by the irregularly spaced cutter link means.

2. In an odd length saw chain having a series of central drive links, a series of pairs of side links pivotally connected to said drive links on opposite sides thereof, said side links including cutter link means mounted on opposite sides of said drive links at regularly spaced intervals, each of said cutter link means having a depth gage portion and a cutter portion integrally formed thereon, an improved, readily detachable means connecting the free ends of said saw chain which, when its free ends are connected and because of its odd length, results in irregularly spaced cutter means, said connecting means comprising; first and second terminal drive links pivotally mounted at opposite ends of said saw chain, a connecting link and a connecting-gage link having end portions pivotally mounted on opposite sides of and in abutting relationship With said first terminal drive link, enlarged circular apertures in the free ends of said connecting link and said connecting-gage link, said apertures having approximately the same diameter as a circular aperture in the free end of said second terminal drive link, a readily removable connecting pin slidably mounted in said apertures, said connecting pin having portions thereon positionable in said second terminal drive link aperture which permits said second terminal drive link to be pivotably supported thereon without any appreciable, relative, longitudinal movement therebetween, said connecting pin also having groove means thereon which cooperate with said enlarged circular apertures of said connecting and connecting-gage links, to permit a relatively minor amount of longitudinal movement of said connecting link and connecting-gage link relative to said second terminal drive link when the saw chain is either in tension or compression thus moving the equi-diameter circular apertures out of alignment and holding the connecting pin in place While at the same time permitting relative pivotal movement of all of the saw chain links, and a depth gage portion mounted on and projecting upwardly from 5 6 the end of said connecting-gage link opposite to the end 2,923,329 2/ 60 Gudmundsen. having the enlarged aperture. 2,930,417 3/60 Consoletti.

References Cited by the Examiner FOREIGN PATENTS UNITED STATES PATENTS 5 651,063 10/37 Germany. 539 6 3 9 97 Appleby 74 25 17,202 9 Great i 1 gg gi g WILLIAM W. DYER, ]R., Primary Examiner. 2,661,228 12/53 Wilson. DONALD R. SCHRAN, Examiner. 2,905,209 9/59 Gudmundsen. 

1. IN A CHAIN SAW CUTTING APPARATUS WHEREIN THE SAW CHAIN NORMALLY COMPRISES A SERIES OF CENTRAL DRIVE LINKS, A SERIES OF PAIR OF SIDE LINKS, MEANS PIVOTALLY CONNECTING SAID PAIRS OF SIDE LINKS TO SAID DRIVE LINKS INCLUDING CUTTER LINK MEANS MOUNTED AT PREDETERMINED DISTANCES ON ALTERNATING SIDES OF SAID DRIVE LINKS, EACH OF SAID CUTTER LINK MEANS INCLUDING A DEPTH GAGE PORTION AND A CUTTER PORTION, THE IMPROVEMENT IN AN ODD LENGTH SAW CHAIN COMPRISING: READILY DETACHABLE CONNECTING MEANS CONNECTING THE FREE ENDS OF SAID ODD LENGTH SAW CHAIN WHICH WHEN CONNECTED RESULTS IN REGULARLY SPACED CUTTRER LINK MEANS, SAID DETACHABLE CONNECTING MEANS COMPRISING A CONNECTING LINK AND A CONNECTING-GAGE LINK POSITIONED IN ABUTTING RELATIONSHIP ON OPPOSITE SIDES OF A FIRST TERMINAL DRIVE LINK AND EACH HAVING AN END PORTION PIVOTALLY MOUNTED THEREON, ENLARGED APERTURES IN THE FREE ENDS OF SAID CONNECTING LINK AND SAID CONNECTING-GAGE LINK HAVING APPROXIMATELY THE SAME DIAMETER AS AN APERTURE IN THE FREE END OF A SECOND TERMINAL DRIVE LINK, A CONNECTING PIN HAVING PORTIONS THEREON WITH THE SAME CONFIGURATION AND SLIGHTLY LESS DIAMETER THAN SAID ENLARGED APERTURES SO THAT UPON ALIGNMENT OF SAID ENLARGED APERTURES, SAID CONNECTING PIN CAN BE SLIDABLY AND REMOVABLY MOUNTED IN SAID APERTURES TO SECURE THE FREE ENDS OF THE SAW CHAIN TOGETHER, MEANS ON THE CONNECTING PIN COOPERATING WITH MEANS ON SAID CONNECTING LINK AND CONNECTING-GAGE LINK TO PERMIT A RELATIVELY MINOR AMOUNT OF LONGITUDINAL MOVEMENT OF SAID CONNECTING LINK AND CONNECTING-GAGE LINK RELATIVE TO SAID SECOND TERMINAL DRIVE LINK WHEN THE SAW CHAIN IS EITHER IN TENSION OR COMPRESSION THUS MOVING THE ENLARGED DIAMETER APERTURES OUT OF ALIGNMENT AND PREVENTING THE CONNECTING PIN FROM BECOMING DISENGAGED, AND A DEPTH AGE PORTION PROJECTING UPWARDLY FROM SAID CONNECTING-GAGE LINK TO TAKE UP SOME OF THE VOID FORMED BY THE IRREGULARLY SPACED CUTTER LINK MEANS. 